As we known, Keepvid has been the dominant online video downloader (especially as the YouTube downloader) for many years. However, this program only works on Windows. If you try to download YouTube video or other streaming video on Mac, it will end in fail. Is there a Keepvid for Mac program that allows you to download YouTube and other streaming videos on Mac OS X (Mountain Lion included)?

The answer is yes! Bigasoft YouTube Downloader Pro for Mac is just the right Keepvid Alternative for Mac! It can help Mac users to fast download YouTube videos in HD (high-definition 720p, 1080p, and 2k), ultra high definition (4K), 3D video and stand definition as well as convert YouTube videos in FLV, WebM, and H.264 to popular video and audio formats. Then it is that easy to play and edit YouTube movies/music on Mac or play Youtube on iPad, iPod, iPhone, Apple TV, PS3 and etc.

Step 1: Find the video you want to downloadSafari, Chrome and Firefox are all supported. Launch one of them, and go to the video sharing website like YouTube to find the video you want to download.

Step 2 Copy and Paste URLCopy the URL of the YouTube video that you want to download; then switch to the interface of Bigasoft Youtube Downloader Pro for Mac and paste the URL to the text box on the left side of Paste URL. (Normally, as soon as you have copied the YouTube video URL, Bigasoft YouTube Downloader Pro will automatically paste the copied URL of YouTube video.)

Step 3: Set desired output formatClick the drop-down menu to the right side of the "Automatically Convert to" to select desired output video format like MP4, MOV, AVI, WMV, 3GP, MPG and etc from the "General Video" category or select desired output audio format like MP3, WMA, WAV, M4A, AIFF and etc from the the "General Audio" category.(Make sure that the "Automatically Convert to" option is checked)

Step 4: Start and finish Download and Convert YouTube videoClick the "Download" button to start and finish converting and downloading YouTube video or audio to Mac.

Step 5 Get the downloaded and converted YouTube videoClick the destination folder link on the right side of "Save to" to get the downloaded YouTube at Download folder or to get the converted YouTube at Convert folder.